Decomposition of nonlinear operators into ´harmonic´ components, with applications to audio signal processing

We show that time-invariant nonhysteretic nonlinear operators K may be decomposed into ´nth-harmonic´ components Kn (n=...,-2, -1, 0, 1, 2,...) consisting of frequencies n₁ F₁+...+n₁F₁, where F₁,..., F₁ are frequencies in the input signal and n₁+...+n₁=n. This is applied to the design of r.f. and a.f. audio signal processors.